南昌市一次连续空气污染过程的气象条件分析

2004年12月8—16日南昌市出现了一次连续空气污染过程。利用城市空气污染观测资料和气象常规观测资料，从天气形势和主要气象要素两个方面，对此次空气污染过程进行了分析。结果表明，此次连续空气污染事件都是出现在风速小、无雨和有雾或霾的气象条件下，高空主要为高压脊的形势或是处在西风槽底的平直气流中，低层大气稳定，中层大气增温明显；地面形势主要为地面高压脊、高压底部或是倒槽前部，地面有弱冷空气南下时不一定能改变污染状况。极厚、极强的逆温层和极小风速的持续存在是造成污染物高浓度最重要的气象条件。此外，地形也是影响南昌市空气质量水平的因素之一。

METEOROLOGICAL CONDITIONS OF A CONTINUOUS AIR POLLUTION PROCESS IN NANCHANG CITY

From the two aspects of synoptic situation and fundamental meteorological elements, the data of air pollution and conventional meteorological observation are employed to analyze an air pollution process occurred in Nanchang city on 8-16 Dec 2004. The result indicates that this continuous air pollution process occurred under the misty or hazy conditions with gentle breeze and no rain. At the high level there is pressure ridge or straight flow in the bottom of westerly trough, while stable atmosphere is dominant at the low level and evident temperature-increase at the middle level. At the surface, however, the predominant system is the pressure ridge, the bottom of the high pressure or the foreside of the inverted trough. Under these conditions, the pollution situation would not change even if weak cold air moves southward through the region. The persistence of extremely thick and strong inversion layer and minimal wind speed is the most important meteorological condition for high concentration pollution. Besides, the terrain also plays one of the important roles to affect the air quality of Nanchang city.